Pump unit

ABSTRACT

A pump unit for use in a tank adapted to be filled with hydraulic fluid is provided and members suspend the pump and motor assembly in the fluid tank normally below the fluid level. The suspending members connect to a cover on the tank by means of vibration dampening means.

United States Patent Torsten C. 0. Montelius Djursholm, Sweden 818,599

Apr. 23, 1969 Mar. 16, 1971 Aktiebolaget lmo-Industri Stockholm, Sweden May 8, 1968 Sweden lnventor Appl. No. Filed Patented Assignee Priority PUMP UNIT 4 Claims, 4 Drawing Figs.

U.S. Cl.

Int. Cl. G0lfll/00, B67d 5/40 [50] Field of Search 103/87, 118, 218; 222/333, 385

[56] References Cited UNITED STATES PATENTS 2,139,370 12/1938 Lauer et a1 103/118 2,319,934 5/1943 Korte et a1. 103/87 3,136,259 6/1964 Bood 103/87 3,172,572 3/1965 Brown et a1 222/385X Primary Examiner-Robert M. Walker Attorney-Oldham and Oldham ABSTRACT: A pump unit for use in a tank adapted to be filled with hydraulic fluid is provided and members suspend the pump and motor assembly in the fluid tank normally below a the fluid level. The suspending members connect to a cover on the tank by means of vibration dampening means.

PATENTED-HARISIQYI 570. 22

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v PATENTEDHARI 6 Ian SHEET'Z UF 4 Fig.2

fowmcvw PUMP rmrr The present invention relates to a pump unit having a pump and associated motor immersed in liquid.

The use in hydraulic systems of pumps and motor units completely immersed in the oil tank of the system is becoming more and more usual. This procedure has been found to present significant advantages, particularly since the construction of both the pump and the motor can be simplified to a considerable extent.

One problem associated with this system is, however, one of mounting the unit in the oil tank so that vibrations from the unit are not transmitted to the surroundings to a disturbing extent. The unit is normally mounted to the bottom of the tank.

This enables rubber vibration absorbers to be mounted between the unit and the tank bottom. The disadvantage with this solution, however, is that rubber is attacked by the majority of hydraulic oils, and hence the effective life time of the vibration absorbers is short. It is also possible to place the unit at the bottom of the tank without vibration absorbers therebetween, and to mount the vibration abosrbers between the tank and the foundation. Vibration of the actual tank to a disturbing extent is prevented in this instance by using a relatively thick plate in the actual tank or parts thereof. This solution is not completely satisfactory either.

In addition, irrespective of the manner in which the vibrations are absorbed, the methods of mouting the unit on the tank bottom used hitherto incur readily perceived difficulties when the unit must be dismantled for inspection, repair or maintenance.

The object of the present invention is to provide an arrangement whereby a pump unit can be mounted in an oil tank in such a manner that the aforementioned difficulties are circumvented. Damping of vibrations in accordance with the invention can be adhieved in a very. simple manner, and installation of dismantling of the unit is rendered much simple.

In accordancw with the present invention, the pump unit is suspended beneath the cover plate of the tank without being connected to the main portion of the tank (walls and bottoms) and vibration damping means are arranged between the pump unit and the main portion of the tank. The pump unit can thus .be suspended from attachment points mounted to the cover and the vibration damping means positioned between the attachments and the cover, wherewith the cover can be rigidly connected to the tank in general. It is also possible, however, to suspend the unit rigidly beneath the cover and arrange vibration damping means between said cover and the main portion of the tank. Whichever system is elected the vibration damping means are situated above the level of the oil and are thus not subject to attack therefrom. Because the unit is secured to the cover and not connected with the tank in general, it can easily be removed by lifting the cover from the tank, whereupon the unit is removed together with the cover.

Associated with the hydraulic system is a control valve to an inlet of which a line extends from the outlet of the pump passes. Furthermore, lines pass from other openings at the valve to the hydraulic operating devices in the system and a return line which opens into the tank for return of oil thereto. This valve can to advantage be placed on the tank cover, suitably with a vibration damping means positioned therebetween. To prevent vibrations from being transmitted from the unit to the valve through the line, the line may consist wholly or partially of a hose. in a suitable embodiment, a substantially vertical hose is attached from the pump outlet through an opening in the lid to a elbow tube, from which an essentially horizontal hose extends to the valve. If the valve is attached to the cover with vibration damping means, however, a rigid line can also be use.

The invention will now be described with reference to the accompanying drawings, in which:

EEG. l shows an oil tank in longitudinal section provided with a unit mounted therein in accordance with the invention;

PEG. 2 shows a section through the line li-ll in FIG. 1;

FZGS. 3 and 4 show in a corresponding manner another embodiment of the invention.

In FIGS. 1 and 2 there is shown an oil tank 1, the greater portion of which is filled with oil during operation. The tank is provided with a cover plate 2 which can be fastened by means of screws to a flange 3 on the upper surface of the tank. A unit consiting of a pump 4 and a motor 5 is arranged in the tank so that during operation at least the larger portion of the unit is immersed in the oil. The construction and design of the pump and motor are not within the purview of the present invention and will not be described in detail. The pump, for instance, may be an [mo-pump. of well-known design and the motor a known type of electric motor, which are combined to form a unit. v

In the embodiment of FIGS. 1 and 2, the unit 4, 5 is suspended by means of three steel wire ropes 6, 7, 8, which are attached to suitable attachment means on the unit and to the attachments in the cover 2. Thus, in the exemplarly embodiment the rope 6 is placed as a loop through two eyes 9 attached in the housing of the pump 4 and an eye 10 attached on the cover. The loop can thus be formed by drawing an appropriately long rope through the eyes and the ends of the loop can then be connected with a rope lock means or the like. The two ropes 7 and 8 are in a similar manner placed as loops through eyes 11, 12, secured to the cover, and around members on both sides of the motor which form part of the feet upon which the motor is normally mounted in the inverted position to that shown.

The eye 10 is formed at the lower end of a bolt 13 which extends up through a hole 14 in the cover 2. The upper end of the cover is provided with nuts 15 which abut the upper surface of a conical, cup-shaped rubber vibration damping means 16, which is fixed in the cover around the hole 14. Similarly, the eyes 11 and 12 are formed on bolts 17, 18 which are connected in the same way with vibration damping means of which only one, 19, is shown in the drawing.

The outlet of the pump 4 is shown at 20. Extending from the outlet is a pressure hose 21, extending up through an opening 22 in the cover 2 to a metal elbow pipe 23, from which a short hose 24 extends to an inlet at a control valve 25, from which lines (not shown) depart to the hydraulic operating devices. The valves 25 is attached to the cover 2 with a resilient support 26 therebetween. Areturn line 27 passes from the valve to a difi'usor 28 in the oil tank.

The vibration damping means 16, 19, which are attached so that they do not contact the oil, effectively dampen all transmission of vibrations from the unit to the cover. The hoses 21, 24 serve to prevent transmission of vibrations from the unit to the valve 25. If the resilient support 26 alone is sufficient to dampen vibration, the hoses can be replaced with rigid conduit.

In the embodiment of FIGS. 3 and 4 the unit (the motor 30 and pump 31) is rigidly connected with the cover 32, since the motor is attached to the under side of a plate 34, which is welded to brackets 35, which in turn are welded to the cover. The cover is fixed to the tank 36 with rubber vibration damping means 37 inserted therebetween.

In this instance the pump outlet is connected with the control valve 33 by means of a conduit 39 drawn through the cover and attached thereto and carrying valve 33, which is attached to the cover by means of the bracket 40.

Since in this instance the connection between the unit and valve is rigid, flexible connections should be provided in the conduits departing from the valve to the hydraulic operating devices.

I claim:

1. A pump unit comprising a fluid tank adapted to be filled with hydraulic fluid to a predetermined fluid level, a detachable cover for said tank, suspending members attached at spaced points to said cover by means of vibration dampening members, a pump and motor assembly suspended in said fluid tank noramlly below said fluid level only by means of said suspending members, and a valve unit mounted on said cover and having a fluid inlet operatively connected to a fluid outlet of the pump by means including a conduit extending through an opening in said cover.

4. A pump unit as in claim 1 where a return line connects between said valve unit and said tank for return of fluid thereto. 

1. A pump unit comprising a fluid tank adapted to be filled with hydraulic fluid to a predetermined fluid level, a detachable cover for said tank, suspending members attached at spaced points to said cover by means of vibration dampening members, a pump and motor assembly suspended in said fluid tank noramlly below said fluid level only by means of said suspending members, and a valve unit mounted on said cover and having a fluid inlet operatively connected to a fluid outlet of the pump by means including a conduit extending through an opening in said cover.
 2. A pump unit as in claim 1 where said conduit is flexible, and resilient means support said valve unit on said cover.
 3. A pump unit as in claim 1 where said suspending members comprise wire ropes.
 4. A pump unit as in claim 1 where a return line connects between said valve unit and said tank for return of fluid thereto. 